Dual pressure control for pneumatically operated apparatus



C. H. RIPPL May 24, 1938.

DUAL PRESSURE CONTROL FOR PNEUMATICALLY OPERATEDAPPARATUS Filed Jan. 15, 1937 2 Sheets-Sheet l FLUID PRESSURE SOURCE MEANS PRESSURE REDUCING FIG.I.

1N VENT OR.

L Y E W m R O W A S E L M M W Y B May 24, 1938. c H RlPPL I 2,118,779

DUAL PRESSURE CONTROL FOR PNEUMATICALLY OPERATED APPARATUS Filed Jan. 15, 1937 2 Sheets-Sheet 2 L l-l B COMPRESSED FLUID SOURCE INVENTOR, CHARLES H. RIPPL.

ATTORNEY.

Patented May 24, 1938 UNITED STATES PATENT OFFICE DUAL PRESSURE CONTROL FOR- PNEU- MATICALLY OPERATED APPARATUS Charles H. Rippl, Cleveland, Ohio, assignor to The Clark Controller Company,

Cleveland,

12 Claims.

This invention relates to fluid pressure operated apparatus and to controls therefor by which different parts of the apparatus may be operated by different fluid pressures.

The invention is particularly applicable to pneumatically operated welding machines and to the pneumatically operated electric timing switches for timing the welding current utilize-d thereby and to the controls therefor whereby the switch may be operated at a high pressure (such for example as the full pressure of the source) and the welding machine may be operated at a reduced pressure; and while the invention has other uses it will be illustrated and described herein as applied to that use.

It is among the objects of the invention:

To provide generally an improved control for fluid pressure operated apparatus;

To provide a control for fluid pressure operated apparatus by which different operative pressures may be applied to the apparatus in an improved manner;

To provide an improved control for fluid pressure operated apparatus whereby high and low pressures may be successively applied to the apparatus;

To provide a control for pneumatically operated welding apparatus by which a relatively low operating pressure may be applied to a welding gun or other welding machines and a relatively high operating pressure may be applied to a welding current timing switch apparatus in controlled sequence.

To provide an improved valve construction for controlling application of pneumatic pressure to a welding current timing apparatus responsive to pressure conditions at a welding gun or other welding machine.

To provide a control for fluid pressure operated apparatus by which a plurality of devices may be operated successively in an improved manner from a common fluid pressure source.

To provide a control for a plurality of fluid pressure operated devices by which one device may be operated responsive to operation of another in an improved manner.

Other objects will be apparent to those skilled in the art to which my invention appertains.

My invention is fully disclosed in the following description taken in connection with the accompanying drawings in which:

Fig. 1 is a diagrammatic view illustrating an embodiment of my invention when used in connection with a welding machine of one type;

Fig. 2 is a diagrammatic view illustrating the embodiment of my invention in connection with a well known gun type of Welding device;

Fi 3 is a view illustrating in modified form a valve arrangement illustrated diagrammatically in Figs. 1 and 2.

Referring to the drawings I have shown genorally at l a welding machine comprising an upper head 2 supporting a pneumatic cylinder 3 in which is reciprocated a piston 4 normally held in an upper position by a spring 5 and arranged to be forced downwardly upon the admission of compressed air to the cylinder above the piston and to move downwardly an upper electrode 5 connected to the piston.

A lower head I has associated therewith a lower electrode 8. Work pieces 9 may be supported on the lower head I and when the upper electrode is moved downwardly the work is engaged be tween the two electrodes and electric current supplied by mains l and I! to the electrodes produces the weld on the work pieces 9.

The parts of the machine just described are illustrated diagrammatically and their exact construction and arrangement constitute no essential part of the present invention and inasmuch as such Welding machines are well known further illustration or description thereof is deemed unnecessary herein.

Illustrated generally at I2 is an electric cur rent timing switch, pneumatically operated and illustrated diagrammatically. The switch I2 comprises a valve housing l3 controlling the application of pneumatic pressure to the switch 12 and the exhausting of the same therefrom in the operation of the switch. The exact construction and arrangement of the parts of the switch l2 constitutes no essential part of the present invention. Such a switch constitutes the subject matter of the co-pending application of Edward G. Beiderman, Serial No. 84,981 filed June 13, 1936 for Improvements in time controlled electric switches, and reference may be had thereto for a fuller showing and description. Likewise the exact construction of the parts within the valve housing I3 constitutes no essential part of this invention, one construction of the same constituting a part of the subject matter of the copending application of Charles H. Rippl, Serial Number 120,362 filed January 13, 1937 for "Imprcvements in pressure control for pneumatically operated switches and reference may likewise be had thereto.

The diagrammatically illustrated timing switch valve comprises a plunger l4 vertically reciprocably supported in a frame supported normally at its lower end Iii upon the frame and having below its lower end a piston rod l1 carrying a piston i3 reciprocable in a cylinder ii! in the valve housing i3. A spring 26 normally holds the plunger down. When the plunger l4 moves upwardiy, a cam 92! thereon engages a cam follower roller on an oscillatable arm 23 and the roller riding over the cam face rocks the arm 23 clockwise against the tension of a spring The cam 25 passes upwardly beyond the roller 22 and then the spring returns the arm counter-clockwise, the arm having a normal position determined by a stop engaging the lower end of the arm and mounted on a panel or other support When the cam 2i returns down wardly it rocks the roller 22 out of its path without moving the arm the roller for this purpose being mounted on a pivoted arm 2?, the rear end of which is normally engaged with a stop 28 by a spring 29.

The tension of the spring 26 may be adjusted by a screw 3b engaging the upper end of the spring and supported on the frame I5.

The arm is secured to a shaft 3| mounted at one end portion to oscillate in a bearing 32 on the frame [5 and at another end portion in a bearing Rigidly secured to the shaft 3| is a pair of switch arms 34-34 having contacts on their upper ends, and a mating pair of contacts 36-36 are mounted on pivoted arms the arms being yieldable against springs til-38.

When in the upward movement of the plunger M above described, the arm 23 is rocked clockwise, the switch arms 3-34 are moved to effect engagement of the pairs of contacts 35--36 and when the arm 23 again rocks counterclockwise the switch arms 34%34 are moved to break the circuit at the contacts. Thus the contacts are maintained closed for a time interval and while closed electric current flows from a pair of supply mains 534 and H35 by wires $86 and I8! through the switch arms 3l'3'l, contacts 36-38 and and switch arms 34--34 through the mains H3 and H to supply welding current as above described.

As fully set forth in the above mentioned copending patent applications, the stroke of the plunger is may be timed to cause the said current impulse to have any desired duration for performing the weld on the work 9, by adjustment of the spring 28, the spring 24, the shape of the operating face of the earn 2!, the rate of admission of air by the valve structure in the housing 53 to the cylinder i9 and in some cases by kinetic energy of an inertia weight 38 on the arm 23.

At 3Q is a source of fluid pressure from which the fluid pressure to operate the switch i2 and the machine l is supplied, under the control of, a valve device 453, comprising a main stationary housing ii, and a valve element 52 of cylinder form reciprocable in a cylindrical bore 43 to control various'fiuid passages to be described. The valve element 52 is normally held in a downward position by a spring that position of the valve element 62 being determined by a stop flange 45, and the up-stroke of the valve element 42 being determined by engagement of the stop flange 45 with a shoulder it. The valve element is arranged to be moved upwardly by an electric winding il acting on a solenoid plunger 48.

Within the stationary housing 4! is a piston vaive l9 of tubular form closed at its upper end and reciprocable in a bore 5d. The piston valve 4.9 is retained in the upper end of its bore by a spring 5! inside of the valve, the tension of the spring being adjustable by a screw 52 which extends outwardly through the housing and is externally adjustable.

The further description of the valve device 40 will be given in connection with a description of its operation which follows.

Fluid under pressure at the source 39 is conducted by a conduit 53 to a duct 54 at the valve device but with the parts of the valve device 4!! in their normal position the pressure is cut off thereat by the valve 49. The fluid is also conducted by a conduit 55 through a pressure reducing device 56 to a conduit 5'! and thence to a duct 58 where the pressure is cut off by the valve 42.

The parts are now ready to operate and with work 9 placed in the machine I, the operator of the apparatus closes a switch 59 and current flows from the supply mains l84--l85 by wires 60-60 to energize the winding 41 and raise the plunger 58 and valve 42.

When the valve 42 moves to its upper position, a duct 6| therein establishes communication from the duct 58 through a duct 62 to a conduit 63 which admits the fluid pressure to the cylinder 3 of the machine l which moves the electrode 6 downwardly to engage the work for welding. The pressure within the cylinder 3 is communicated by a conduit 64 back to the valve device where it communicates with a duct 65 which opens inwardly into the valve cylinder 50. This duct is normally sealed by the upper end of the valve 49. The pressure in the conduit 64 at the start of the machine piston 4 downwardly is less than the pressure applied to the cylinder 3 by the conduit 63 as is common with piston and cylinder devices such as that of the machine I which are designed to develop a high final pressure within the cylinder, but after the piston 4 has moved to engage the electrodes and the full pressure from the conduit 63 builds up in the cylinder 3, the pressure in the conduit 64 correspondingly builds up and therefore after the electrodes 6 and 8 are fully engaged with the work 9, this built up back pressure communicated to the valve 49 through the duct 65 moves the valve downwardly against the spring 5| to a bottom position at which the lower end 56 of the valve engages a stop 6 In this position an annular chamber 68 in the outer wall of the valve 49 establishes communication between the duct 54 above referred to and a duct 69 to which is connected a conduit 10 leading to the valve housing E3 of the switch l2 and the pressure from the source is now applied through this conduit to operate the switch I2 to send a welding current impulse through the work 9, as above described.

The weld is thus completed and then the operator may open the switch 59 and the spring 44 will restore the valve 42 to its original position.

In this position of the Valve, the cylinder 3 may exhaust its pressure backwards through the conduit 53 to the duct 62 and thence, as shown, through the duct GI and out to atmosphere by a duct H. Similarly, the conduit 64 may discharge backward through the duct 65 and by way of ducts l2, l3 and 74 to atmosphere. The ducts l2, l3 and 74 likewise provide a discharge for the pressure in the cylinder 50 above the valve 49 so that the valve may be restored by its spring 5|; and finally, the pressure at the switch l2 may be discharged backward through the conduit 10 to the duct 69 which is now out off by the valve 49 and thence by way of ducts I4, I5 and 16 may discharge to atmosphere.

In the above described operation, it will be apparent that the machine I is supplied by pressure from the source 3I at less than the source pressure due to the pressure reducing device 56. There are numerous reasons why machines such as that indicated at I are preferably operated at relatively low pressure. Particularly is this true when the machine I is of. the hand operated type. In some instances, the machines I built by a welding machine manufacturer are designed to be operated at a relatively low pressure whereas operation of the switch I2 may better be effected to better control and time a welding current impulse by higher pressure. On the other hand, it is always desirable to be able to supply all of the operating pressure from a single source such 39 and with the arrangement above described both pressures are available, one for the machine I and the other for the switch I2.

The pressure reducing device 56 may be of any suitable or known construction, its structure not constituting an essential part of the present invention, it being only essential that when fluid is supplied thereto as by the conduit 53 at one pressure, it will flow out therefrom as by the conduit 51 at a reduced pressure. Such devices are well known in this art and a further description is deemed unnecessary.

As will be clear from the foregoing description, the valve device 40 is automatic, a single operating movement given thereto as for example, by the plunger 48, supplying the reduced pressure to the machine I and automatic means within the valve 40 (the valve 49) supplying the full pressure of the source to the switch I2 but only after the electrodes 8 and 9 are fully engaged with the work whereby it is not possible for the switch I2 to operate until the electrodes are engaged with the work.

In order to prevent the accumulation of pres sure (or vacuum) under the valve 42, a bleeder duct I42 is provided communicating with the atmosphere and with the under side of the valve, and a similar duct I45 under the valve 49 is pro vided for a like purpose.

referably the upper end of the valve 49 is provided with an annular bead I43 at which the upper end of the valve seals the duct 05. The pressure applied to the valve is therefore communicated to less than its full diameter but after the valve starts to move and the seal is broken at the bead I43, the full end area of the valve is exposed to the pressure so that its operation will be positive and it will move the full stroke promptly. If, however, the seal at the bead I43 should leak, then the full end area of the valve would be exposed to the pressure prematurely and to avoid this, a bleeder duct I44 is provided communicating with the atmosphere and with the upper end of the valve 49 outside of the annular bead I43.

In Fig. 2 is illustrated the application of my invention to the type of welding machine ordinarily referred to as a welding gun shown generally at IT. The current timing switch being shown at I8 and a valve device at I9.

The welding gun 11 comprises a cylinder having a piston 8I therein returnable by a spring 82, the piston 8I arranged to move the electrode 03 toward a stationary electrode 84 to clamp the work 85 therebetween preparatory to welding it. The electrodes 03 and 84 are connected by wires 86 and 81 to switch arms 88-B8 which upon operation of the timing switch I8 as a whole, es-

tablish a welding circuit by wires 89-89 to the supply mains 90-90. The timing switch device 18 may be identical with that shown in Fig. 1 at l2, and comprising the valve housing I3 of that figure.

The welding gun '51 has, in the frame thereof a duct 9| communicating at one end with the cylinder 80 and at the other end closed off by an operable piston valve 92; and the duct 9I has a branch duct 93 normally communicating with an exhaust duct 94 around a reduced diameter neck portion or the piston valve 92.

The duct 9i also communicates with a branch duct 90 connected to a back pressure conduit 91.

Pressure is supplied to the gun 11 through a conduit I98 communicating with a duct 99 normally shut ofi by the piston valve 92. The piston valve 92 is normally held in its inoperative position by a spring I00 and is provided with a button 1!. When the operator presses the button IOI, the valve 92 is moved downwardly as illustrated in the drawings which causes a large diameter portion I02 of the valve to shut off the exhaust 03-94 and to open a pressure supply through the ducts 99 and 9I to operate the gun 11, as described; and upon releasing the button IN, the spring I00 returns the valve 92 to out off the pressure supply and open the exhaust.

Guns of this construction are well known in the art and it is believed that the brief description and, in some respects, diagrammatic illustration thereof herein is sufiicient.

The valve device I9 comprises a stationary housing 503 having cylindrical bore I04 therein in which reciprocatcs a piston valve I05 of tubular form closed at its lower end. A spring I06 within the valve holds it downwardly, the

pressure being adjustable by a screw IIlI extending through the wall of the housing for external adjustment. In the upward movement of the valve to be described, it is stopped on a stop I08 on the housing,

The source of pressure is shown diagrammatiback pressure in the conduit 91 as explained in connection with the form of Fig. l is at a reduced pressure but as the electrodes 83 and 84 are moved toward and upon the work 85, the pressure in the conduit 91 builds up. This pressure is communicated from the conduit 91 through a duct M4 to the valve cylinder I04 and when it reaches the value for which the spring I 06 is adjusted, the valve is raised and by means of an annular chamber I I5 in the outer wall of the valve, establishes communication from the duct I I3 to a duct I I5 communicating with the switch operating conduit 98.

Full force pressure is thus applied to the switch and operates it to provide the timed current impulse.

After the weld is made and the button IOI is released, as above described, the pressure in the conduit 91 is exhausted out through the exhaust 94 by way of the duct 93 and the valve I05 is returned downwardly by the spring I06.

Thereupon the conduit 98 communicates by means of the duct H6, and a duct ill with an annular chamber H8 in the outer wall of the valve I and thence communicates with the atmosphere by a duct H9 whereby pressure from the valve housing I3 is exhausted.

As in the first described form, the gun Tl may be operated at a reduced pressure from the source I09 and the timing switch (8 may be operated at full pressure and the automatic valve arrangement l9 insures that the electrodes of the welding gun will be fully engaged with the work before the switch 18 can operate. This form is simpler than that shown in Fig. 1 because of the fact that the pressure exhausts for the gun cylinder 88 and for the conduit 91 are on the gun structure itself.

The valve I05 preferably seals the duct H4 on an annular bead M6 which functions like the bead I43 above described and a bleeder duct I4! is provided for the purposes described in connection with the bleeder duct I44 of Fig. 1. A bleeder duct I48 is provided to function like the bleeder ducts M5 and M2 of the form of Fig. 1.

3 illustrated one form. of structure ch may be in practice for the diagrann atically i lustrated valve of Figs. 1 and 2. The back pressure conduit We communicates with a cylinder llii formed in a housing member l22 which is threadedly jointed to another housing member I23 at see. A piston I25 reciprocates in the cylinder 52E, being held downwardly by a spring 526, and being supported by a piston rod 22? extending upwardly through the housing pier her i2 2 into the open lower end of the hous- .ing member i235 and having a pin E23 projected through the rod above the housing 22.

The housing member 23 has a cylinder l29 therein in which is reciprocable a guide Kill. A valve stem i3! is projected downwardly through the guide Hill and a pin N32 is projected through the rod below the guide 30.

The red, at its upper end, extends through a small bore E33 into a cylindrical passageway I34 and the bore H3 is sealed by a packing I35 which is compressed. around the valve stem by a washer 53$ held tightly thereupon by a spring !3? surrounding the stem 53! and reacting at one end upon the washer 536 and at the other end upon the guide l-iil.

Upon the upper end of the valve stem i3! is mounted a disc form valve iilB which is held downwardly upon an annular valve seat I39 by the spring 1351. Above the valve 638, the housing I23 is connected to the source pressure conduit Mn. A switch pressure supplying condu t Id! communicates through the side of the housing with the passageway i534.

Fluid under pressure in the conduit Mil is cut off from the conduit Mi normally by the valve (33. When the back pressure in the conduit 529 has reached a value determined by the spring M5, the piston 25 is moved upwardly and the upper end of the piston rod it? engages the lower end of the valve stem i135 lifts the valve i555? whereupon the full pressure from the conduit M9 is communicated to the conduit Ml for the purposes hereinbefore described in connection with Figs. 1. and 2.

Although I have illustrated and described my invention in connection with a pressure reducing means by which one pressure operated device such as a welding apparatus may be operated at one pressure and another devi e such as an elecric switch may be operated at another pressure,

my invention may be practiced and the advantages of the pressure operated valve operating after initiation of operation of one of the devices, may be enjoyed, if both devices are operated at the same pressure; or ii the second-to-operate device is the one to operate at the reduced pressure; or, in fact, if the two devices are operated from entirely separate sources or fluid pressure.

Although I have illustrated the welding current to the welding electrodes 838 -'a of li -8 as supplied directly from current supply mains, it is to be understood that it may be supplied from the secondary of the transformer as is, in some applications, the customary practice.

Changes and modifications may be madev with in the scope and spirit of my invention without sacrificing its advantages and within the scope of the appended claims.

I claim:

1. In a fluid pressure system for operating two devices one at high velocity and the other at low velocity, each device having an expansible fluid pressure chamber, a source of relatively high fluid pressure and a source of relatively low fluid pressure, conduit means between the lower pressure source and the chamber of the low velocity device, an operable valve controlling the conduit to admit fluid pressure to the chamber of the lower velocity device to operate it, and to cause pressure in the chamber to rise toward the pressure of the source, a fluid pressure operable valve having conduit communication with the said chamber of the low velocity device and operable upon rise of pressure in the chamber to a predetermined value, conduit means between the source of high fluid pressure and the high velocity device and controlled by the fluid pressure operable valve to admit high source pressure to the chamber of the high velocity device upon operation of the fluid pressure operable valve.

2. The system described in claim 1 and in which the operable valve is electro-magnetically 0per-- able and means is provided to restore it, and conduit means is provided by which when it is restored it effects exhausting of the pressure communicated to the fluid pressure operable valve.

3. The system described in claim 1 and in which the operable valve is provided with means to restore it and conduit means is provided by which when it is restored it exhausts the pressure communicated to the fluid pressure operable valve.

4. In a fluid pressure system for operating two devices one operable by relatively high fluid pressure and the other operable by relatively low fluid pressure, each device having an expansible fluid chamber, a source of relatively high fluid pressure and a source of relatively low fluid pressure, conduit means between the lower pressure source and the chamber of the low pressure operable device, an operable valve controlling the conduit to admit fluid pressure to the chamber of the low pressure operable device to operate it, and to cause sure in the chamber to rise toward the pressure of the source, a fluid pressure operable valve having conduit communication with the said chamber of the low pressure operable device and operable upon rise of pressure in the chamber to a predetermined value, conduit means between the source of high fluid pressure and the high pressure operable device and controlled by the fluid pressure operable valve to admit high source pressure to the chamber of the high pressure operable device upon operation of the fluid pressure operable valve.

5. The system described in claim t and in which means is provided to discontinue the application of fluid pressure to the pressure operable valve and means is provided to then restore it, and, upon restoring, it exhausts fluid pressure from the chamber to one of the devices.

6. The system described in claim 4 and in which means is provided to discontinue the application of fluid pressure to the pressure operable valve and means is provided to then restore it, and, upon restoring, it exhausts fluid pressure from the chamber of the high pressure operable device.

'7. The system described in claim 4 and in which means is provided to restore the operable valve, and, upon restoring, it discontinues the application of fluid pressure to the pressure operable valve and means is provided to then restore the pressure operable valve.

8. The system described in claim 4 and in which means is provided to restore the operable valve, and upon restoring, it discontinues the application of fluid pressure to the pressure operable valve and means is provided to then restore the pressure operable valve, and, upon restoring, it exhausts pressure from the chamber of one of the devices.

9. The system described in claim 4 and in which means is provided to restore the operable valve, and, upon restoring, it discontinues the application of fluid pressure to the pressure operable valve, and means is provided to then restore the pressure operable valve, and, upon restoring, it exhausts pressure from the chamber of the high pressure operable device.

10. The system described in claim 4, and in which means is provided to restore the operable valve, and, upon restoring, it exhausts pressure from the chambers of both of the devices.

11. The system described in claim 4 and in which means is provided to restore the operable valve, and, upon restoring, it discontinues the application of fluid pressure to the pressure operable valve, and means is provided to then restore the pressure operable valve.

12. The system described in claim 4 and in which means is provided to restore the operable valve, and, upon restoring, it exhausts pressure from the chambers of both devices, and discontinues the application of pressure to the pressure operable valve, and means is provided to then restore the pressure operable valve.

CHARLES H. RIPPL. 

